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Default Solar Power

One of the proposed ways to extend the range of an electric car is through the addition of solar panels. A solar cell or photovoltaic (PV) cell is a device that converts light energy into electrical energy by the photovoltaic effect, a solar panel is a group of solar cells packaged together into one unit. Thus a vehicle (or any area) covered with solar panels exposed to sunlight will produce usable electric energy. In an EV this means that solar panels can be used either for on board charging or directly powering the controller/motor. PV cells are a non polluting renewable source of electricity with no moving parts and little required maintenance.

Common Questions About Solar Power and EVs.

Can an EV run purely on the energy generated by solar power at highway speeds?
Yes! Purpose built vehicles are able to achieve very impressive speeds using just the power of the sun. In the World Solar Challenge these solar cars compete against each other in a race across Australia running purely on sunlight and a small battery pack. The winner of the 2007 race, the Dutch Nuon Solar team, averaged 90km/h (56mph) in their solar car Nuna4 pictured below:

Can a normal EV conversion run purely on the energy generated by solar power at highway speeds?
No. The reason that these solar cars can travel at such impressive speeds is because they are some of the most efficient vehicles in the world. These cars can travel at highway speeds using about the same amount of energy as your hair dryer, about 10% of the energy required by a normal sized car. They have extremely efficient solar cells covering 8m2 (86 sqft) to gain as much power as possible. Using Solar Cells on a standard conversion will give around a 5-10% increase in range and the ability to trickle charge the batteries when parked in the sun but not yield enough energy for anywhere near highway speeds.
Why aren't Solar panels a viable option as a range extender?
The reason is due to the power to weight (and cost) ratio of solar panels:
Quote:
'For some figures, typically you could fit about 200W of solar panels onto a car. Solar panels generally provide the equivalent of 5 hours at their rated power per day, i.e about 1kWh for a 200W panel per day, which is about 5km of extra range in a small vehicle. 5km may sound somewhat useful, but 1kWh worth of extra batteries weighs and costs less than a 200W solar panel! Also unless you're very careful with your installation, the increase in aerodynamic drag will quickly negate any extra range they can provide.*'
*Quote by Ian Hooper
Has anyone tried it before?
Yes. There are some enthusiasts who have installed solar panels on their EVs with some success. For example the University of Maine Solar Vehicle Team added a substantial 1kW solar array to their Chevy S-10 EV which gave them a 10-15 mile range using solar power alone at moderate speeds compared to 100 miles with the battery pack.



Contributors: mattW
Created by mattW, 12-18-2007 at 06:44 AM
Last edited by mattW, 01-11-2008 at 10:28 AM
17 Comments , 17210 Views
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Old 06-07-2011, 09:29 AM
jimy_f_84 jimy_f_84 is offline
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Default Re: Solar Power

Hi, new here.

My thoughts for my build is to have a solar panel that i could have it charge the batteries while i am at work, sine i spend there about 10 hours. any thoughts, is it doable?
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Old 06-07-2011, 10:16 AM
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Ziggythewiz Ziggythewiz is offline
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Default Re: Solar Power

Not unless your car looks like the one above.

However, a small panel can keep provide all your 12v charging needs if you don't drive at night, and more panels could provide an additional 2 miles or so of range.
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Old 06-14-2011, 05:51 AM
NZero NZero is offline
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Default Re: Solar Power

I disagree. Having competed in the Australia race the sun solar car challenge I love the idea of panels.

My Honda (E-Lude in the garage) could have a 140watt panel mounted on the roof for instance. With a good charge controller it could give my 120v pack 1 amp every hour so over 10 hours I've gained 10Ah and in my 100Ah pack thats another 10%.

If my battery runs flat somewhere I know that given some time I can limp back home. However given where I live a small turbine (800 watt) that folds up is far more viable.
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Old 06-14-2011, 06:43 AM
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Default Re: Solar Power

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Originally Posted by NZero View Post
thats another 10%.
If you have a 20 mile range, that's 2 extra miles, as I said above. I think solar is a cool addition, but if your battery runs flat somewhere, you can walk home long before the solar will get you there.
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Old 06-15-2011, 12:23 AM
NZero NZero is offline
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Default Re: Solar Power

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Originally Posted by Ziggythewiz View Post
If you have a 20 mile range, that's 2 extra miles, as I said above. I think solar is a cool addition, but if your battery runs flat somewhere, you can walk home long before the solar will get you there.
But I have 100km range so thats another 10km and I would rather have that extra push then walk 10km lol. Not that I have panels installed but its only a matter of time.
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Old 06-15-2011, 08:06 AM
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Ziggythewiz Ziggythewiz is offline
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Default Re: Solar Power

How are you getting 62 miles off a 100ah pack? What's your kwh/m?

Assuming no other possible form of transportation, I'd walk the 10km home (2 hour stroll) watch 2 full football games, then walk back to the car and drive it home.
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Old 06-15-2011, 05:08 PM
T1 Terry T1 Terry is offline
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Default Re: Solar Power

Solar charging is part of the plan with my conversion but it's just a little different to the norm. Mine is a 36 ft bus converted to a motorhome with 1kw of solar on the roof. Naturally at the moment it can't be a full electric propulsion system so it will start out as a hybrid but as the technology improves I hope to finally do away with the ICE altogether. A big motor, big controller and lots of batteries, outside reality at the moment so an electric assist using a smaller ICE will have to do for the moment.

T1 Terry
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Old 06-16-2011, 12:16 AM
NZero NZero is offline
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Default Re: Solar Power

Quote:
Originally Posted by Ziggythewiz View Post
How are you getting 62 miles off a 100ah pack? What's your kwh/m?

Assuming no other possible form of transportation, I'd walk the 10km home (2 hour stroll) watch 2 full football games, then walk back to the car and drive it home.
120v @ 100ah = 100 Kilometers of driving (at avg 85km/h)
I dont know miles etc but I'm sure from that you could tell me my useage.

Car is a stripped out Honda Prelude with light mag wheels and a low drag co efficient.
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Old 06-16-2011, 07:56 AM
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Default Re: Solar Power

Have you driven 100 km on a single charge? Even if you could take 100ah from a 100ah battery, which you can't, you can only run it down to 80% DOD (50% recommended for longer battery life).
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